It shouldn't be that horrible anymore to do it cross browser like that, at least as long as you follow web standards and ignore Internet Explorer, requiring Windows 10 support there.
And it would make these apps, of course, absolutely tiny.
How about using that as a starting point, and have that Electron alternative focus on making cross-browser development as painless as possible instead via built in Javascript shims/polyfills where necessary, and special API calls to integrate it into the underlying OS of course (OS native notifications etc)?